Hot-melt extrusion as a method for producing sustained-release pharmaceutical formulations that are based on water-soluble polymers, such as polyethylene oxides, poly(methacrylate) derivatives, poly(ethylene-co-vinyl acetates), poly(vinyl acetate-co-methacrylic acids), epoxy resins and caprolactones is known. The International Patent Publication WO 97/49384 discloses pharmaceutical formulations comprising a hot-melt extrudable mixture of a therapeutic compound and a high molecular weight poly(ethylene oxide). International Patent Publication WO 02/35991 discloses active agent-containing spherical particles produced by a hot-melt extrusion/spheronization process. A large variety of thermoformable polymeric materials is listed for the production of the particles, such as wax, proteins, cellulosic polymers, polyols, acrylic polymers, fats, glycerin, lipids, fatty acids, fatty alcohols, carbomers, polyvinyl polymers and combinations thereof. U.S. Pat. No. RE 33,093 discloses a bioadhesive extruded single or multi-layered thin film comprising 20 to 92 percent by weight of a hydroxypropyl cellulose, 5 to 60 percent by weight of a homopolymer of ethylene oxide, 0-10 percent by weight of a water-insoluble polymer such as ethylcellulose, propyl cellulose, polyethylene, and polypropylene, and 2-10 percent of a plasticizer.
It would be desirable to provide new sustained-release compositions of which the release rate of the biologically active ingredient can be varied and/or controlled, particularly that the release rate of the biologically active ingredient can be adjusted to the specific need of administering the biologically active ingredient or to the specific biologically active ingredient.